A mathematical model for the multi-mode resource investment problem

This paper presents an exact model for the resource investment problem with generalized precedencerelations in which the minimum or maximum time lags between a pair of activities may varydepending on the chosen modes. all resources considered are renewable. the objective is to determinea mode and a start time for each activity so that all constraints are obeyed and the resource investmentcost is minimized. project scheduling of this type occurs in many fields for instance, constructionindustries. the proposed model has been inspired by the packing problems. in spite of thefact that it needs a feasible solution to start for conventional models, the new model has no need fora feasible solution to startup with. computational results with a set of 60 test problems have beenreported and the efficiency of the proposed model has been analyzed.